{VERSION 5 0 "APPLE_PPC_MAC" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 }{CSTYLE "Hyperlink" -1 17 "" 0 1 0 128 128 1 2 0 1 0 0 0 0 0 0 1 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 } {CSTYLE "" 0 21 "" 0 1 0 0 0 1 0 0 0 0 2 0 0 0 0 1 }{CSTYLE "" -1 256 "" 1 24 0 0 0 0 0 1 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 257 "" 1 10 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 258 "" 1 18 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 259 "" 1 18 0 0 0 0 1 0 0 0 0 0 0 0 0 1 } {CSTYLE "" -1 260 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 261 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 262 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{CSTYLE "" -1 263 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 1 " -1 3 1 {CSTYLE "" -1 -1 "Times" 1 18 0 0 0 1 2 1 2 2 2 2 1 1 1 1 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}}}{EXCHG {PARA 257 "" 0 "" {TEXT 256 7 "RECORDS" }}{PARA 259 "" 0 "" {TEXT 259 11 "Tevian Dray " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 258 "" 0 "" {TEXT 257 34 "co pyright 1998-2000 by Tevian Dray" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 260 "" 0 "" {TEXT 258 36 "What does the phonograph record see?" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{SECT 1 {PARA 3 "" 0 "" {TEXT -1 14 "Initialization" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 49 "restar t:with(linalg):with(plots):with(plottools):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 2594 "# Record\n\n# Release 4:\n#Machine:=substring(in terface(version),39..41):\n# Release 5.1:\n#Machine:=substring(interfa ce(version),41..43):\n# Fixed?\nMachine:=IBM:\n\nArrow:=proc(base,dir, color)\n local Dir:\n global Machine:\n if Machine=`IBM` or Machine =`DEC` or Machine=`SUN` then\n Dir:=base+dir\n else\n Dir:=dir \n fi;\n arrow(base,Dir,0.02,0.05,0.1,color)\nend:\n\nrsol2:=vector( [cos(Omega*t)*x[0]+cos(Omega*t)*t*v[x]\n\011+sin(Omega*t)*y[0]+sin(Ome ga*t)*t*v[y]-rho,\n\011-sin(Omega*t)*x[0]-sin(Omega*t)*t*v[x]+\n\011co s(Omega*t)*y[0]+cos(Omega*t)*t*v[y]]):\n\ndd:=disk([0,0],1,color=wheat ):\nrho:=0:\n\nFix:=proc(pos,vel,vframe,time,steps,rot)\n local G,tt, aa,MM,rsol,ll,ff,av,i,vx,vy,rsol3,t:\n if evalb(vframe=`ROT`) then\n \+ av:=evalm(vel-rot*[pos[2],-pos[1]]):\n vx:=av[1]:\n vy:=av[2] :\n else\n vx:=evalm(vel)[1]:\n vy:=evalm(vel)[2]:\n fi:\n rs ol3:=[cos(rot*t)*pos[1]+cos(rot*t)*t*vx\n\011+sin(rot*t)*pos[2]+sin(ro t*t)*t*vy,\n\011-sin(rot*t)*pos[1]-sin(rot*t)*t*vx\n\011+cos(rot*t)*po s[2]+cos(rot*t)*t*vy]:\n G:=[seq(0,i=0..steps)]:\n G[1]:=display(Arr ow([0,0],[-0.25,0],color=green),dd):\n for i from 1 to steps do\n \+ tt[i]:=rot*i*time/steps:\n aa[i]:=Arrow(pos,[vx,vy]*i*time/steps,co lor=blue):\n MM[i]:=matrix([[cos(tt[i]),-sin(tt[i])],[sin(tt[i]),co s(tt[i])]]):\n rsol[i]:=multiply(MM[i],rsol3):\n ll[i]:=plot([rs ol[i][1],rsol[i][2],t=0..i*time/steps],\n\011\011color=red,thickness=2 ):\n ff[i]:=Arrow([0,0],[-0.25*cos(tt[i]),-0.25*sin(tt[i])],color=g reen):\n G[i+1]:=display(ll[i],aa[i],ff[i],dd):\n od:\n display(G ,scaling=constrained,insequence=true,axes=NONE);\nend:\n\nRot:=proc(po s,vel,vframe,time,steps,rot)\n local H,f2,t2,M2,l2,Start2,v2,a2,av,i, vx,vy,rsol3,t:\n if evalb(vframe=`ROT`) then\n av:=evalm(vel-rot*[ pos[2],-pos[1]]):\n vx:=av[1]:\n vy:=av[2]:\n else\n vx:=vel [1]:\n vy:=vel[2]:\n fi:\n rsol3:=[cos(rot*t)*pos[1]+cos(rot*t)*t *vx\n\011+sin(rot*t)*pos[2]+sin(rot*t)*t*vy,\n\011-sin(rot*t)*pos[1]-s in(rot*t)*t*vx\n\011+cos(rot*t)*pos[2]+cos(rot*t)*t*vy]:\n H:=[seq(0, i=0..steps)]:\n H[1]:=display(Arrow([0,0],[-0.25,0],color=green),dd): \n f2:=Arrow([0,0],0.25*[-1,0],color=green):\n for i from 1 to steps do\n t2[i]:=rot*i*time/steps:\n M2[i]:=matrix([[cos(t2[i]),sin( t2[i])],[-sin(t2[i]),cos(t2[i])]]):\n l2[i]:=plot([rsol3[1],rsol3[2 ],t=0..i*time/steps],color=red,thickness=2):\n Start2[i]:=evalm(mul tiply(M2[i],pos)):\n v2[i]:=evalm(multiply(M2[i],[vx,vy]*i*time/ste ps+pos)-Start2[i]):\n a2[i]:=Arrow([Start2[i][1],Start2[i][2]],[v2[ i][1],v2[i][2]],color=blue):\n H[i+1]:=display(l2[i],a2[i],f2,dd): \n od:\n display(H,scaling=constrained,insequence=true,axes=NONE);\n end:\n" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{SECT 1 {PARA 3 "" 0 "" {TEXT -1 15 "Getting started" }}{PARA 0 "" 0 "" {TEXT -1 216 "Straight line motion in the plane traces out a complicated path as seen by a r otating observer. The needle of a phonograph moves radially towards t he center of the record, yet traces out a long spiral on the record!" }}{PARA 0 "" 0 "" {TEXT -1 223 "Replace the record by a blank sheet of paper, and the phonograph needle by a red pen. Furthermore, allow th e needle to start anywhere, and move in any fixed direction with const ant speed. What curve is drawn on the paper?" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 53 "We showed in class that t he equation of this curve is" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 44 "r[rel]:=rsol2[1]*r[hat]+rsol2[2]*theta[hat];" }}}{PARA 0 "" 0 "" {TEXT -1 40 "where the initial position of the pen is" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "r[0]:=[x[0],y[0]];" }}}{PARA 0 "" 0 "" {TEXT -1 27 "and its initial velocity is" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "v[fix]:=[v[x],v[y]];" }}}{PARA 0 "" 0 "" {TEXT -1 35 "(A derivation of this equation for " }{XPPEDIT 18 0 "r[rel]" "6#&%\"r G6#%$relG" }{TEXT -1 80 ", as well as the differential equation it sol ves, can be found in the worksheet " }{HYPERLNK 17 "2D Rotations" 1 ": usersB:tevian:maple:ph429:2Drot.mws" "" }{TEXT -1 49 "; the equation i s also derived in Class Notes 1.)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 10 "Note that " }{XPPEDIT 18 0 "v[x]" "6#&%\" vG6#%\"xG" }{TEXT -1 5 " and " }{XPPEDIT 18 0 "v[y]" "6#&%\"vG6#%\"yG " }{TEXT -1 49 " denote the initial velocity with respect to the " } {TEXT 260 11 "nonrotating" }{TEXT -1 37 " frame. The initial velocity in the " }{TEXT 261 8 "rotating" }{TEXT -1 18 " frame is given by" }} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 39 "v[rel]:=eval(subs(t=0,diff(r [rel],t)));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{SECT 1 {PARA 3 "" 0 "" {TEXT -1 5 "Demos" }} {PARA 0 "" 0 "" {TEXT -1 151 "The following demos graph the path of th e pen, both as seen by the nonrotating observer (blue vector), and as \+ seen by the rotating observer (red line)." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 93 "First, we set define some paramete rs. The angular velocity of the record (in radians/second " }{TEXT 263 16 "counterclockwise" }{TEXT -1 14 ") is given by " }{XPPEDIT 18 0 "Omega" "6#%&OmegaG" }{TEXT -1 21 "; a typical value is " }{XPPEDIT 18 0 "Omega=1" "6#/%&OmegaG\"\"\"" }{TEXT -1 46 ". The number of seco nds the demo will run is " }{XPPEDIT 18 0 "T" "6#%\"TG" }{TEXT -1 21 " , a typical value is " }{XPPEDIT 18 0 "T=5" "6#/%\"TG\"\"&" }{TEXT -1 44 ". The total number of pictures is given by " }{XPPEDIT 18 0 "N" " 6#%\"NG" }{TEXT -1 39 ", so that the time between pictures is " } {XPPEDIT 18 0 "T" "6#%\"TG" }{TEXT -1 1 "/" }{XPPEDIT 18 0 "N" "6#%\"N G" }{TEXT -1 27 ". A reasonable choice for " }{XPPEDIT 18 0 "N" "6#% \"NG" }{TEXT -1 4 " is" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 5 "N: =5;" }}}{PARA 0 "" 0 "" {TEXT -1 55 "(A smoother animation is obtained for larger values of " }{XPPEDIT 18 0 "N" "6#%\"NG" }{TEXT -1 2 "; " }{XPPEDIT 18 0 "N=10" "6#/%\"NG\"#5" }{TEXT -1 41 " works fairly well. But large values of " }{XPPEDIT 18 0 "N" "6#%\"NG" }{TEXT -1 74 " ma y also take significantly longer to run. See what works well for you. )" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 90 "Fina lly, you should make a choice of how you want the graphics to be displ ayed, using any " }{TEXT 262 3 "one" }{TEXT -1 25 " of the following 3 lines" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "plotsetup(inline): " }{TEXT -1 26 " (graphs in worksheet)" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 18 "plotsetup(window):" }{TEXT -1 29 " (graphs in M aple window)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "plotsetup(x 11):" }{TEXT -1 41 " (graphs in separate X window)" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 378 "In the figures you will constr uct, the blue arrow represents the linear motion seen by an inertial o bserver, while the red curve represents the motion seen by the rotatin g observer. (The green arrow is to help you keep track of the rotatio n.) Think of the tip of the blue arrow as containing a red pen which \+ writes on the record as the record rotates beneath the (moving) pen." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 166 "The de mo consists of 2 functions, one from the point of view of each referen ce frame. The first of these shows what the nonrotating observer sees , and takes the form" }}{PARA 262 "" 0 "" {TEXT -1 1 " " }{XPPEDIT 18 0 "Fix(start,velocity,vframe,T,N,Omega" "6#-%$FixG6(%&startG%)velocity G%'vframeG%\"TG%\"NG%&OmegaG" }{TEXT -1 1 " " }}{PARA 0 "" 0 "" {TEXT -1 6 "Here, " }{XPPEDIT 18 0 "N" "6#%\"NG" }{TEXT -1 2 ", " }{XPPEDIT 18 0 "T" "6#%\"TG" }{TEXT -1 2 ", " }{XPPEDIT 18 0 "Omega" "6#%&OmegaG " }{TEXT -1 23 " are as defined above, " }{XPPEDIT 18 0 "start" "6#%&s tartG" }{TEXT -1 31 " denotes the initial position, " }{XPPEDIT 18 0 " velocity" "6#%)velocityG" }{TEXT -1 35 " denotes the initial velocity, and " }{XPPEDIT 18 0 "vframe" "6#%'vframeG" }{TEXT -1 79 " specifies \+ whether the initial velocity is with respect to the fixed observer (" }{MPLTEXT 0 21 13 "vframe:=`FIX`" }{TEXT -1 28 ") or the rotating obse rver (" }{MPLTEXT 0 21 13 "vframe:=`ROT`" }{TEXT -1 2 ")." }}{PARA 0 " " 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 16 "For example, try" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "Fix([-1,0],[1/4,0],`FIX`,4 ,N,-10);" }}}{PARA 0 "" 0 "" {TEXT -1 55 "which is roughly what happen s when you play a record. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 263 "" 0 "" {TEXT -1 242 "(To run the animations, use the buttons at t he top; for inline display, you will first need to click on the figure . For either inline or Maple window display, you can find out what th e buttons do by turning on Balloon Help in the Help menu.)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 78 "To see this from \+ the reference frame of the rotating observer, use the command" }} {PARA 261 "" 0 "" {XPPEDIT 18 0 "Rot(start,velocity,vframe,T,N,Omega" "6#-%$RotG6(%&startG%)velocityG%'vframeG%\"TG%\"NG%&OmegaG" }{TEXT -1 1 " " }}{PARA 0 "" 0 "" {TEXT -1 67 "which takes the same parameters. \+ Compare your previous output with" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "Rot([-1,0],[1/4,0],`FIX`,4,N,-10);" }}}{PARA 0 "" 0 " " {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 86 "You can reproduce the r esults in Figure 10-4 on page 389 of Marion and Thornton using " } {XPPEDIT 18 0 "Omega=1" "6#/%&OmegaG\"\"\"" }{TEXT -1 25 ", the initia l positition" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "MTstart:=[- 1/2,0]:" }}}{PARA 0 "" 0 "" {TEXT -1 46 "one of the initial velocities (and total time " }{XPPEDIT 18 0 "T" "6#%\"TG" }{TEXT -1 15 " as indi cated):" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "MTv[a]:=[0,1]*3/2 :" }{TEXT -1 31 " (T=0.86)" }{MPLTEXT 1 0 19 "\n MTv[b]:=[0,1]*4/5:" }{TEXT -1 30 " (T=2.9)" } {MPLTEXT 1 0 20 "\nMTv[c]:=[0,1]*9/20:" }{TEXT -1 29 " \+ (T=17.3)" }{MPLTEXT 1 0 21 "\nMTv[d]:=[0,1]*0.328:" }{TEXT -1 26 " (T=5.0)" }{MPLTEXT 1 0 28 "\nMTv[e]:=[1,1]*0.47/sq rt(2):" }{TEXT -1 12 " (T=3.83)" }{MPLTEXT 1 0 29 "\nMTv[f]:=[1,1]* 0.283/sqrt(2):" }{TEXT -1 9 " (T=3.3)" }}}{PARA 0 "" 0 "" {TEXT -1 15 "and specifying " }{MPLTEXT 0 21 5 "`ROT`" }{TEXT -1 5 " for " } {MPLTEXT 0 21 6 "vframe" }{TEXT -1 30 ". Try it! Try other choices! " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 "Fix(MTstart,MTv[e],`ROT` ,3.83,N,1);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}}{MARK "2" 0 }{VIEWOPTS 1 1 0 3 2 1804 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }